CHALCOPYRITE with GOETHITE and a single SPHALERITE CRYSTAL

Chalcopyrite is a mineral composed of copper, iron, and sulfur, recognized as the primary source of copper ore. Its chemical composition is represented by the formula CuFeS2, and it crystallizes within the tetragonal system. The mineral exhibits a brassy to golden yellow hue and possesses a hardness rating of 3.5 to 4 on the Mohs scale, with a distinctive, green-tinged black streak.

Goethite is a mineral belonging to the diaspore group, characterized as iron(III) oxide-hydroxide, specifically in its α-polymorph form. It is commonly found in soil and low-temperature environments, including sedimentary contexts. Historically recognized for its use as a pigment, particularly brown ochre, goethite has been identified in ancient paint samples from the Lascaux caves in France. The mineral was first documented in 1806, based on specimens from the Hollertszug Mine in Herdorf, Germany, and is named in honor of the German polymath Johann Wolfgang von Goethe.

Goethite is composed of iron oxyhydroxide with ferric iron as its primary element. It serves as a significant component of rust and bog iron ore. The mineral exhibits a hardness of 5.0 to 5.5 on the Mohs Scale and has a specific gravity ranging from 3.3 to 4.3. While it typically forms massive structures, goethite can also appear as prismatic needle-like crystals, often referred to as "needle ironstone."